The present invention relates to supply chain management, and particularly to a manufacturing management system and method with real-time yield information.
In the supply of products, the supply chain performs the functions of material purchasing, transformation of materials into intermediate and finished products, and distribution of finished products to clients. Supply chain management has become important in meeting the goals of reduced inventory, increased productivity, and enhanced competitiveness. Manufacturing and distribution facilities have limited resources and capacity, hence, not every client request may be met. For example, some requests may be promised but unfulfilled, some clients may receive inadequate supply, and other requests may be rejected. Consequently, effective management of capacity in supply chain management, without excess capacity loss is important for product suppliers who need to control manufacture or distribution.
In the supply chain, clients transmit demands to a supplier. The demand may include a request for a particular quantity of a device design by a specific date. The supplier plans its internal or external manufacturing schedule according to these received demands, and allocates capacity for manufacturing products to satisfy each client. After receiving orders corresponding to demands from clients, the supplier begins manufacturing the products.
In the foundry business, two business models, die buy and wafer buy models, are widely used. In the die buy model, clients provide orders and demands with die quantity to a supplier, and without considering the impact on product yield. In the wafer buy model, clients provide orders and demands with wafer quantity to a supplier, and take risk of product yield. In product manufacturing, product yield fluctuates, trending up with manufacturing experience or trending down with abnormal events. In the die buy model, if the product yield trends up, the output die quantity will exceed client requirements, and the supplier must bank or scrap excess dies, thereby increasing production cost. If the product yield decreases, the output die quantity will not meet client requirements.
FIG. 1 shows a conventional manufacturing cycle. Conventionally, a client 100 determines orders 100 according to yield history information, and transmits the orders 100 to a supplier. The supplier then manufactures products corresponding to the orders 110 (120), and performs circuit probe test on the products (130). The yield test result is fed back to the client 100 as yield history information for subsequent orders. Since clients determine orders according to the product yield in the wafer buy model, real-time yield information is important for clients in making order request decisions. In the conventional manufacturing cycle, however, the yield information is obtained only after the products have been manufactured and tested, and the yield information can be only referred to in the next manufacturing cycle. Thus there may be a delay in product to market time, and lost competitiveness. There is no effective mechanism to provide real-time yield information for demand planning and WIP (Work In Process) adjustment, to thereby meet client demands and reduce supplier cost.